In a quiet Federal Way garage, a group of students is getting the chance to do something they’d never get away with at school – build and run a thermonuclear reactor.

The project aims to reimagine what science class might look like, and nudge dozens of kids into careers in science and technology.

It started with a guy named Carl Greninger, and his realization that tight budgets and fear of lawsuits have pushed out much of the fun, dangerous stuff from high school science labs, leaving “nothing sharper than silly putty.

"I walked into a classroom and I saw a science teacher. And he had a string and a paper cup. And he says, well, we're studying physics, and I looked back at the kids and I saw the word 'lame' tattooed across their foreheads. And I said, I can do better than this in my garage,” he says.

Carl's secret lab

So he decided to do exactly that. Greninger is a Microsoft IT manager, and doesn’t have any nuclear engineering experience per se. But he settled on building a nuclear fusion reactor in his house, and inviting teenagers to help.

Greninger is a lanky guy in his white lab coat and glasses, a touch of mischief in his eyes. His flair for the dramatic is on display as you enter the reactor room through a hidden door, disguised as shelving in his garage.

Inside is the Farnsworth Fusor, a relatively simple reactor dating from the 1960s that uses electricity to fuse molecules of a hydrogen isotope. It’s about the size of a refrigerator, and since Greninger bankrolled the thing himself (he declines to cite a figure, but says it was well into six-figure territory), he retained creative control. As a result, it looks exactly as cool as you would hope it would be: shiny chrome, purple lighting, lots of those yellow-and-black radiation hazard signs. And yes, it does have some duct tape.

Beneath a one-ton shield sits the actual reactor, which resembles a motorcycle engine. Inside, high voltage creates what's called a negative potential well – think of it almost like a little black hole. It pulls molecules from all sides toward a point, and some of them slam together hard enough to fuse.

“And that's pure plasma at about 300 million degrees Fahrenheit,” Greninger says. “It's actually hotter than the surface of the Sun”

Wait, what?

A machine like this raises a few obvious questions: Is it safe? Is it legal?

As for the law, Greninger is apparently in the clear. Because the fusor doesn't use radioactive fuel, it falls under state regulations rather than the federal Nuclear Regulatory Commission. The Washington Office of Radiation Protection did pay Carl a visit once after a neighbor raised some concerns. Health physicist Mike Brennan inspected the facilities. He saw the safeguards, the shielding and the radiation dose meters everyone wears.

“From a safety point of view I was entirely satisfied very quickly,” Brennan says.

He concluded it was probably safer than a lot of the stuff in other people’s garages, like, say, a welding rig. In fact, he was so impressed with Greninger's setup, he returned several times to give talks to the students

“I think that it is not only safe, but he is teaching safety, so a culture of safety is radiating out from his secret lab.”

Not your usual extracurricular activity

Safety is pretty crucial when you remember that Greninger isn’t just running a reactor in a Federal Way cul de sac, he’s inviting children over to play with it. Twelve high school students meet every Friday at Carl’s house, take in a physics lecture and then fire up the reactor.

The students are a mix of boys and girls, MIT-bound seniors and impressionable sophomores. They grab white lab coats and clipboards, and start the 73-point activation process. Pumps are activated, detectors tested, voltage slowly increased. Two students flank the machine with Geiger counters, sweeping for any possible leaks.

At one point, senior Raymond Maung walks in wearing a bright silver spacesuit, carrying a thermos of liquid nitrogen.

“In class, the most physics we do is bouncing rubber balls. This kind of experience is definitely priceless,” Maung says.

As the electricity increases, a counter measures neutron production: the product of nuclear fusion.

A new way of learning

If Greninger has his way, some of these kids will restock the talent in America’s nuclear industries – making advances in energy, nuclear medicine and materials science.

The significance of this kind of work isn’t lost on kids like Krystal, a 15-year-old from Auburn who’s been with the group since 7th grade. She's known as the youngest fusioneer. Krystal says working on the reactor has shown her that parts of science that had seemed like drudgery in the classroom, like the math and the careful controls, actually really matter.

“I'm going to be honest: As a seventh grader I had probably the worst grades. And joining this group made me a 4.0 student. This group gave me a new way of learning,” she says. .

That kind of learning may soon be available to a lot more people. One of the students is designing software to run the reactor remotely, so kids could soon be doing nuclear fusion experiments from their desks at school. If that happens, science class might not seem so tame anymore.